The present invention relates to a hairiness controlling device for a spun yarn (hereinafter simply referred to as xe2x80x9cyarnxe2x80x9d) in a winder such as an automatic winder, and a winder such as an automatic winder having the hairiness controlling device and a doffing device.
For example, a supply bobbin produced by a ring spinning is transferred to an automatic winder, which detects a defect in the yarn while joining yarns from a large number of supply bobbins to rewind them into corn- shaped or cheese-shaped packages. This rewinding by the automatic winder is a process for tensioning the yarn unwound from the supply bobbin while using a large number of yarn guides to guide the yarn to form a package. Thus, a yarn formed by twisting short fibers is subjected to friction each time it passes through the yarn guide, thereby, after rewinding, increasing the amount of hairinesses present in the yarn in the supply bobbin before rewinding.
Thus, for a rewinding process by a winder such as an automatic winder, a hairiness controlling device is provided in a yarn running path to suppress hairinesses. A hairiness controlling device has been proposed which rotates a plurality of friction disks to falsely twist a yarn run through the disks to intertwine hairinesses with fibers in order to suppress the hairinesses. This hairiness controlling device rotates each disk for false twisting while simultaneously feeding a yarn so that the tension of the yarn rewound into a package is controlled based on a rotation speed of each disk and a running speed of the yarn.
When running of the yarn and rotation of each disk are started simultaneously with the start of rewinding, the yarn may jump out from between the disks unless the tension of the yarn is controlled to an appropriate value.
This is because immediately after the start of rewinding, the yarn is subjected to a very low tension and is thus moved in such a manner as to follow rotation of each disk. Thus, if the yarn jumps out from between the disks, a hairiness suppressing process cannot be carried out and the yarn cannot be continuously rewound.
In addition, an automatic winder forms a package by rewinding a yarn around a winding bobbin gripped by a cradle, the yarn having its hairinesses suppressed by a hairiness controlling device, and performs a doffing operation when the package becomes full. The doffing operation in the automatic winder is started when the package becomes full. Once the package has become full, winding of the yarn is suspended. Subsequently, the yarn is cut between the supply bobbin and the package, and the full package is unloaded from the cradle, which is supporting the package. Subsequently, a new winding bobbin is installed on the cradle, and a yarn threading operation is performed to install the yarn from the supply bobbin on the new winding bobbin. The yarn remains threaded through the hairiness controlling device at least during the yarn threading operation of the doffing operation.
When, however, the yarn from the supply bobbin side is moved for the doffing operation (the yarn threading operation), the yarn may be broken due to a contact resistance with each disk of the hairiness controlling device. The breakage of the yarn affects the doffing operation (yarn threading operation) performed by the automatic winder.
It is an object of the present invention to provide a hairiness controlling device that can start, simultaneously with the start of yarn running, stabilizing a yarn run through disks.
It is another object of the present invention to provide a winder comprising a hairiness controlling device and which can perform a smooth doffing operation.
A hairiness controlling device according to the present invention rotates a plurality of disks to falsely twist a spun yarn run through the disks while applying a feeding force to the yarn. With this hairiness controlling device, simultaneously with the start of running of the yarn, an operation is started for varying a rotation speed of each of the disks depending on a running speed of the yarn.
Simultaneously with the start of running of the yarn, the operation is started for varying the rotation speed of each of the disks depending on the running speed of the yarn, thereby setting the tension of the yarn at an appropriate value at the start of the running.
With a hairiness controlling device according to the present invention, the rotation speed of each of the disks is raised as the running speed of the yarn rises.
While keeping the tension of the yarn at an appropriate value, the rotation speed of each disk and the running speed of the yarn can be raised to corresponding values required for yarn rewinding.
The tension of the yarn arises from the rotation speed of each disk and the running speed of the yarn; the yarn is tensed to increase its tension when the difference between a feeding speed (low) of the yarn corresponding to the rotation speed of each disk and the running speed (high) of the yarn is increased. Accordingly, if the yarn is tensed immediately after the start of yarn running by lessening the rotation speed of each disk in proportion to the running speed of the yarn, the tension of the yarn can be rapidly raised to an appropriate value.
With a hairiness controlling device according to the present invention, each of the disks is rotated at a low speed before the yarn starts to run.
Each of the disks is rotated at a low speed before the yarn starts to run, thereby reducing yarn breakage caused by a contact resistance between the yarn and each disk when the yarn starts to run.
A hairiness controlling device according to the present invention has a member for acting on and bending a preceding part of the yarn run through the disks.
By bending the yarn when it starts to run, the tension of the yarn can be rapidly raised to an appropriate value.
The hairiness controlling devices according to the above inventions are applied to a winder for forming a package by winding the yarn unwound from a supply bobbin, around a winding bobbin rotated by drive means. These hairiness controlling devices provide high effects particularly when applied to an automatic winder comprising a yarn monitor for detecting a yarn defect and a yarn joining device for joining a yarn end on a supply bobbin side and a yarn end on a package side together.
A hairiness controlling device according to the present invention rotates a plurality of disks to falsely twist the yarn run through the disks while applying a feeding force to the yarn, and has guide means for holding the yarn in a central portion between the disks when the yarn starts to run.
By using the guide means to hold the yarn when the yarn starts to run, the yarn run through the disks is stabilized.
With a hairiness controlling device according to the present invention, after the yarn has started to run, the guide means is inactivated when the tension of the yarn has reached an appropriate value. Once the tension of the yarn has reached an appropriate value, the yarn runs stably through the disks. While the yarn is running stably, the guide means is inactivated to stop contacting with the yarn, thereby preventing the yarn from being excessively damaged.
With a hairiness controlling device according to the present invention, the guide means pushes the yarn into the central portion between the disks before the start of running of the yarn.
By pushing the yarn into the central portion between the disks before the start of yarn running, the yarn can start to run more stably. If the disks are rotated at a low speed when the yarn is pushed in, yarn breakage can be prevented during the push-in operation.
The hairiness controlling devices according to the above inventions are applied to a winder for forming a package by winding the yarn unwound from a supply bobbin, around a winding bobbin rotated by drive means. These hairiness controlling devices provide high effects particularly when applied to an automatic winder comprising a yarn monitor for detecting a yarn defect and a yarn joining device for joining a yarn end on a supply bobbin side and a yarn end on a package side together.
A winder according to the present invention comprises a hairiness controlling device having a plurality of disks and a doffing device, the doffing device performing a doffing operation with the yarn threaded through the hairiness controlling device, the yarn connecting to a supply bobbin. With this winder, when the yarn threaded through the hairiness controlling device is moved during the doffing operation, the disks of the hairiness controlling device are rotated.
By rotating each disk when the yarn is moved during the doffing operation, the contact resistance between each disk and the yarn run through the disks is lowered to reduce yarn breakage occurring when the supply-side yarn is moved through the disks.
With a winder according to the present invention, each disk is rotated at a lower speed than during normal winding when the yarn is moved during the doffing operation.
Since the yarn moves at a low speed during the doffing operation, each disk is rotated at a low speed to set the tension of the yarn at an appropriate value.
With a winder according to the present invention, rotation of each disk is started simultaneously with the start of the doffing operation.
The rotation of the disks is started simultaneously with the start of the doffing operation, thereby eliminating the necessity of complicated control.